test(billing): validate stripe customer id enforcement

backend/src/billing.rs

@@ -902,3 +902,109 @@ mod tests {
         ));
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use sqlx::SqlitePool;
+    use sqlx::sqlite::{SqliteConnectOptions, SqlitePoolOptions};
+    use std::str::FromStr;
+    use std::sync::{Mutex, OnceLock};
+
+    fn env_lock() -> &'static Mutex<()> {
+        static LOCK: OnceLock<Mutex<()>> = OnceLock::new();
+        LOCK.get_or_init(|| Mutex::new(()))
+    }
+
+    #[allow(unused_unsafe)]
+    fn set_stripe_secret_key(value: Option<&str>) {
+        match value {
+            Some(v) => unsafe { std::env::set_var("STRIPE_SECRET_KEY", v) },
+            None => unsafe { std::env::remove_var("STRIPE_SECRET_KEY") },
+        }
+    }
+
+    struct StripeSecretKeyGuard {
+        previous: Option<String>,
+    }
+
+    impl StripeSecretKeyGuard {
+        fn set(value: Option<&str>) -> Self {
+            let previous = std::env::var("STRIPE_SECRET_KEY").ok();
+            set_stripe_secret_key(value);
+            Self { previous }
+        }
+    }
+
+    impl Drop for StripeSecretKeyGuard {
+        fn drop(&mut self) {
+            set_stripe_secret_key(self.previous.as_deref());
+        }
+    }
+
+    async fn test_pool() -> SqlitePool {
+        let connect_options = SqliteConnectOptions::from_str("sqlite::memory:")
+            .expect("valid sqlite memory url")
+            .create_if_missing(true);
+
+        let pool = SqlitePoolOptions::new()
+            .max_connections(1)
+            .connect_with(connect_options)
+            .await
+            .expect("connect sqlite memory db");
+
+        sqlx::migrate!("./migrations")
+            .run(&pool)
+            .await
+            .expect("run migrations");
+
+        pool
+    }
+
+    #[tokio::test]
+    async fn billing_new_panics_without_stripe_secret_key() {
+        let _lock = env_lock().lock().expect("acquire env lock");
+        let _env = StripeSecretKeyGuard::set(None);
+
+        let pool = test_pool().await;
+        let query = Query::new(pool.clone());
+        let command = Command::new(pool);
+        let robot = Robot::test_stub();
+
+        let result = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| {
+            Billing::new(query, command, robot)
+        }));
+
+        let panic_payload = match result {
+            Ok(_) => panic!("constructor should panic when STRIPE_SECRET_KEY is missing"),
+            Err(payload) => payload,
+        };
+        let panic_msg = if let Some(msg) = panic_payload.downcast_ref::<&str>() {
+            (*msg).to_string()
+        } else if let Some(msg) = panic_payload.downcast_ref::<String>() {
+            msg.clone()
+        } else {
+            String::new()
+        };
+
+        assert!(
+            panic_msg.contains("missing STRIPE_SECRET_KEY environment variable"),
+            "unexpected panic: {panic_msg}"
+        );
+    }
+
+    #[tokio::test]
+    async fn billing_new_accepts_non_empty_stripe_secret_key() {
+        let _lock = env_lock().lock().expect("acquire env lock");
+        let _env = StripeSecretKeyGuard::set(Some("sk_test_dummy"));
+
+        let pool = test_pool().await;
+        let billing = Billing::new(
+            Query::new(pool.clone()),
+            Command::new(pool),
+            Robot::test_stub(),
+        );
+
+        assert_eq!(billing.stripe_secret_key, "sk_test_dummy");
+    }
+}

backend/src/command.rs

@@ -332,3 +332,56 @@ impl Command {
         Ok(())
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use sqlx::SqlitePool;
+    use sqlx::sqlite::{SqliteConnectOptions, SqlitePoolOptions};
+    use std::str::FromStr;
+
+    async fn test_pool() -> SqlitePool {
+        let connect_options = SqliteConnectOptions::from_str("sqlite::memory:")
+            .expect("valid sqlite memory url")
+            .create_if_missing(true);
+
+        let pool = SqlitePoolOptions::new()
+            .max_connections(1)
+            .connect_with(connect_options)
+            .await
+            .expect("connect sqlite memory db");
+
+        sqlx::migrate!("./migrations")
+            .run(&pool)
+            .await
+            .expect("run migrations");
+
+        pool
+    }
+
+    #[tokio::test]
+    async fn create_tenant_rejects_empty_stripe_customer_id() {
+        let pool = test_pool().await;
+        let command = Command::new(pool);
+
+        let tenant = Tenant {
+            pubkey: "tenant_pubkey".to_string(),
+            nwc_url: String::new(),
+            nwc_error: None,
+            created_at: 0,
+            stripe_customer_id: "   ".to_string(),
+            stripe_subscription_id: None,
+            past_due_at: None,
+        };
+
+        let err = command
+            .create_tenant(&tenant)
+            .await
+            .expect_err("empty customer id must be rejected");
+
+        assert!(
+            err.to_string().contains("stripe_customer_id is required"),
+            "unexpected error: {err}"
+        );
+    }
+}

backend/src/robot.rs

@@ -254,3 +254,23 @@ async fn set_cached(
         },
     );
 }
+
+#[cfg(test)]
+impl Robot {
+    pub fn test_stub() -> Self {
+        let keys = Keys::generate();
+        let client = Client::new(keys);
+
+        Self {
+            secret: String::new(),
+            name: String::new(),
+            description: String::new(),
+            picture: String::new(),
+            outbox_client: client.clone(),
+            indexer_client: client.clone(),
+            messaging_client: client,
+            outbox_cache: std::sync::Arc::new(Mutex::new(HashMap::new())),
+            dm_cache: std::sync::Arc::new(Mutex::new(HashMap::new())),
+        }
+    }
+}